The present invention relates to a capture system for electronically actuated keyboard musical instruments, such as electronic and pipe organs, electronic pianos, and the like, wherein a plurality of different combinations of control switch settings can be programmed into the organ for recall and activation at a later time.
Capture systems for organs and other keyboard musical instruments are well known in the art and have been used extensively to enable a performer to recall and automatically implement a combination of tab switches previously set into the organ. Early organ tab preset systems were entirely mechanical in nature and typically comprised various mechanical interconnections between the tab switches and the voicing control system of the organ. Not only were these systems complicated, expensive and difficult to maintain, but they occupied a substantial amount of space in the organ console.
One of the first advances which was realized in the art of organ tab preset systems came about with the introduction of electromechanical devices, which enabled the bulk of the preset system to be reduced somewhat and improved reliability of operation. There were still numerous problems with such systems, however, due to the cost of the electomechanical devices and their susceptibility to mechanical failure. Furthermore, their response time was quite slow in comparison to present day electronic devices, and the noise produced by the relays was objectionable. The next advancement came with the introduction of photoelectric devices which, although a substantial improvement over the bulky, mechanical relays and solenoids, were costly and required a light source. Additionally, the photoelectric devices were relatively slow in operation and their operating characteristics tended to vary with time.
With the development of modern electronic switches, such as field effect transistors and the like, it became possible to switch on and off the various voices of the organ by means of low voltage DC control signals. Since the electronic switches are activated by DC voltages, a minimum of interface circuitry is required between the memory and the electronic switch. On the early organ tab preset systems which utilized these solid state memory devices, many such devices were required because one terminal of each device was required to convey tab information to and from the memory. Since many organs have a very large number of tabs, a correspondingly large number of terminals from the memory of memories were required. This resulted in greatly increased costs and complexity of the system and increased maintenance problems.
More recently, the well known technique of multiplexing has been applied to organ tab preset systems. This type of system requires some sort of memory to which the tab information is stored and retrieved, and several systems have employed a form of shift register memory. A problem with this type of system, is that the number of shift registers required is quite large in order to handle the large number of preset combinations. Other prior art systems, such as that disclosed in U.S. Pat. No. 3,699,839, require a plurality of memories with complex input and output circuitry necessary to store the tab settings and then retrieve them at a later time for implementation.